Evaporator for refrigerating machines



2 sheets-sheet 1 Inventor' c. sTEENsTRUP. EVAPQRATOR FOR REFRIGERATING MACHINES Filed April 17, 1937 Aug. 11, 1942.A

ls Attr'neg.

Aug. ll, 1942. C, sTE'ENsTRUP 2,292,803

EVAP'ORATOR FOR REFRIGERATING MAHINEs Filed April 17. 1957 2 sheets-sheet 2 Patented Aug. 11, 1942 AUNrrao As'rnTE:

EVAPORATOB FOR BEFRIGERATING. MACHINES Christian Steenstrup,-Schenectady, N. Y., assignor to General Electric Company,

New York a corporation of Application April 17, 1937, Serial 1Y0/137,521

- l A4 Claims. (-Cl. 62126) My inventionrelates to -evaporators for refrigerating machines.

It is an object of my and an arrangement whereby liquid refrigerant may be trapped and maintained distributed along the length of Vsaid conduit to provide substantially vuniform heat absorbing capacity throughout the length of the conduit without invention to provide an evaporator1 for -refrigerating machines which is Aprovided with a` refrigerant circulating conduit;

the necessity of maintaining the conduit completely flooded with liquid refrigerant.

Furtherobjects and advantages of my invention will become apparent as the following description proceeds, vand the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to -the accompanying drawings in which Fig. 1 is' a front sectional. elevational view of a household refrigerator provided with an evaporator embodying my invention. Fig. 2 is an enlarged sectional view of a portion of thev evaporator shown in Fig.l 1; Fig. 3 is a sectional view taken along the line 3--3 of Figy'2; Fig. 4 is a perspective view of another embodiment of my invention; Fig. 5 is an en- Alarged sectional view along the line 5-5 of Fig. 4; and Fig. 6 is a sectional view along the -line 6-6 of Fig. 5.

Referring now tothe drawings, in Fig. 1 I have shown a household refrigerating machine comprising a thermally insulated cabinet III mounted fon a' metal s tand II and provided with a food storage compartment I2. In a compartment 9 below the cabinet is arranged a refrigerating machine comprising a motor and compressor casing I3, a condenser- I4 and a liquid receiver orI iioat valve chamber I5. Within the food storage compartment l2 is mounted an evaporator Ii which is connected in the refrigerant circuit of frigerant lines I1 and Il respectively. The condenser circulation 'of air produced by` operationvof a 2I- and being discharged therefrom through louvers 22. f

Duringl the operation of thel refrigerating machine gaseous refrigerantfiscompressed by opthe refrigerating machine by inlet and outlet re-V II-and the casing vIl are cooledbythe erant has collected in the receiver I5 a ioat.

therein rises and allows the refrigerant to, flow frcmthe chamber I5 through the liquid line I1 intoa conduit 25 of the evaporator I6. The liquid refrigerant within the evaporator I6 is vaporized by the absorption of heat from the air within the compartment I2 yand' the vaporized refrigerant is withdrawn 'from the evaporator through the suction line I8 and thereby returned to casing I3.

During the active periods \ofv operation of the refrigerating machine liquid and gaseous refrigerant are continuously circulated through'the evaporator conduitwvhich, therefore, operates as'` an evaporator ofthe non-floodedtype. However;` when the refrigerating machine is stopped there is a tendency for the liquid Irefrigerant in the evaporator to collect at the lower end thereof during the inactive periods ofthe machine and thereby make the heat-absorbing 'capacity greater in the lower than in the upper portion ofthe evaporator. It is therefore desirable to provide some arrangement for preventing the accumu-v lation of all the refrigerant at one end of the y evaporator in such a manner as to concentrate the heat-absorbing capacity in one portion o f the evaporator. In order to distribute evenly the Y heat-absorbing capacity of" the evaporator I-pro vide a plurality of pockets or reservoirs to vtrap refrigerant throughout small amounts of liquid the length of the evaporator so thatJ during the idle period liquid refrigerant is available in sub-4 stantially allparts of the evaporator and heat .may be absorbed uniprovided with formly through out the area thereof.

As shown in Figs. 2 and 3, evaporator I6 comprises front and back metal sheet portions or elements 26 and 21 respectively. The sheet 26 isi identations stamp ed or embossed therein and forming the conduit .25 and a plurality of small reservoirs 28 comprising a series of substantially identical enlargements of the eration .of the compressor within casing Il and of air over the condenser and is liquefied, ancil the liquid Il to the receiver I5 through a-connection 24.

' When a predetermined amount of liq'uid refrigrefrigerant flows from the condenser conduit arranged ati'ntervals along the conduit and extending downwardly therefrom. The pair of sheets 26 and 21 are then secured-together by welding, brazing or in any other suitable manner to provide a pressure-tight evaporator. When the evaporatoris connected in the circuit of the refrigerating machine, the liquid line I1 is connected to the end of the evaporator at the upper end' thereof as indicated at 29 and the suction line .I8 is connected at the lower endas indicated at 30. A 'Y During operation of the evaporator I6, liquid and gaseous refrigerant are vadmitted to the up'- per end of the; conduit 25 ai .d flow downwardly through the conduit, portions of vthe liquid refrigerant being vaporized and the vapo'rized rea the heat' transfer wall of line I8. The conduit is made of sufficient cross-sectional area that the streams of gaseous refrigerant-may flow therethrough over the pools of liquid refrigerant without forcing the liquid refrigerant to pass in slugs through the Aconduit. Liquid refrigerant is therefore trapped and retained in each of the reservoirs 28 and there is liquid refrigerant throughout the entire area of the evaporator which is capablel of absorbing heat from the air passing over the surface of the evaporator. Furthermore, any oil or lubricant owing into the evaporator with vthe refrigerant will tend to float on the surface of the refrigerant in the reservoirs and be carried along with the gaseous refrigerant. Reservoirs 28 therefore afford ready removal of lubricant from the evaporator. During the idle periods of the yrefrigerating machine when refrigerant is not being supplied to the evaporator, small amounts of liquid refrigerant are maintained `in the reservoirs and are available through the length of the conduit 25 for absorbing heat, and there is, therefore, a uniform distribution of the heatabsorbing capacity of the evaporator during the inactive or idle periods of the refrigerating machine.

In Iiigs '."i 5,`v and 6 I have shown another embodiment my invention. The evaporator shown in Fig. 4' comprises an air cooling portion or heat transfer Wall 3i and afreezing tray shelf or heat transfer wall 32 at right angles thereto. The shelf 32 is provided with end pieces 33 whereby the evaporator may be secured within a refrigerator cabinet. The air cooling portion 3| is provided with a refrigerant header 34 and a depending refrigerant' circulating conduit 35 communicating at both ends with the header. The header 34 is maintained normally about half both the active andinactlve periods of the re- .frigerating' machine.

While I have shown and described my invention in connection with a household refrigerating machine, other applications will readily be lapparent to those skilled in the art. I do not therefore desire my invention to be limited to the particular embodiments shown and describedY and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An evaporator of the non-fioodedtype for a refrigerating machine including a sheet metal wall having a sinuous conduit formed therein.

means for supplying liquid refrigerant to said conduit during the active periods of operation of said machine. `and means including a plurality of small reservoirs formed at intervals along said conduit for trapping liquid refrigerant therein to maintain portions of liquid refrigerant distributed along said conduit during the nned with iiquid refrigerant and the conduit :s is

`. lating conduit 36' and at intervals along the con` duit 36 are provided pockets or reservoirs 31 extending downwardly therefrom `and in communication therewith. The reservoirs 31 perform the same function as the reservoirs 28 shown on the evaporator of Fig. 1, and the shelf conduit thus operates as an evaporator of the non-flooded type. i

During the operation of the evaporator shown in Fig. 4, liquid refrigerant is admitted to the evaporator from a liquid line 38 and flows through a shelf inlet conduit 33 formed in the evaporator and thence into the shelf conduit 36. Part of the liquid refrigerant is trapped in the reservoirs 31 below the path of gaseous refrigerant and theremainder flows with the stream4 of gaseous refrigerant from conduit 36 through ashelf outlet connection I0 .and into the lower end of the passage 35. A circulation of the refrigerantin the passage 35 is produced by the refrigerant admitted thereto from the conduit 40. Gaseousrefrigerant is withdrawn from the header above the level of liquid refrigerant therein through a suction line 4i. During the idle periodsof the refrigerating machine when nov refrigerant is being admitted to the evaporator from the .line v38 the liquid refrigerant trapped in the reservoirs31 is available for oool.

ing articles such as shelf 32.

freezing'trays placed on the provided a simple and effective arrangement for maintaining even distribution of refrigerant throughout the passages of an evaporator during From the foregoing it is evident that I have the path of,

streams of gaseous; refrigerant flowing towards inactive periods of said machine to provide substantially uniform heat absorbing capacity throughout the length of said conduit.

2. An evaporator of the non-flooded type for a refrigerating machine comprising sheet metal plurality of indentations formed in one of said sheets at intervals along said conduit for trapping small quantities of liquid refrigerant therein and for maintaining liquid refrigerant distributed along said conduit during the inactive periods of said machine to provide substantially uniform heat absorbing capacity throughout the length of said conduit.

3. An evaporator of the non-hooded type for a refrigerating machine comprising sheet metal portions vproviding a wall to bev cooled, means including an indentation in at least one of said sheet metal portions for providing an extended refrigerant circulating conduit to cool said wall. means for supplying liquid refrigerant to said conduit during the period of oper-ation of said machine, and means including a plurality of small reservoirs formed in one of said metal portions and extending downwardly from and in communication with said conduit at intervals along the length thereof for trapping liquid refrigerant and for maintaining liquid refrigerant distributed along said conduit during the inactive periods of said machine to. provide substantially uniforml heat absorbing capacity throughout the length of said conduit.

4. An evaporator comprising a pair of elements of sheet material secured together to provide a heat transfer wall, liquid refrigerant and an refrigerant; said evaporator having a conduit embossed in the material and extending back and forth across a face ofV said wall and connected to said inlet and said outlet. said conduit being enlarged at spaced intervals from `said inlet to said outlet to provide a series of substantially identical reservoirs for trapping and retaining quantities of refrigerantgin pools below and in communication with, the

said outlet. l

CHRISTIAN STEENSTRUP.

an inlet for receiving' outlet for vaporized'- 

